static RectAndMD5 smallestRectAndMD5Containing(L<RectAndMD5> l, int x, int y) {
  new Lowest<RectAndMD5> b;
  for (RectAndMD5 r : unnull(l))
    if (r.r.contains(p))
      b.put(r, rectPixels(r));
  ret b!;
}

static RectAndMD5 smallestRectAndMD5Containing(L<RectAndMD5> l, Pt p) {
  ret smallestRectAndMD5Containing(l, p.x, p.y);
}